scholarly journals Transgenic mice overexpressing ornithine and S-adenosylmethionine decarboxylases maintain a physiological polyamine homoeostasis in their tissues

1997 ◽  
Vol 323 (2) ◽  
pp. 457-462 ◽  
Author(s):  
Ritva HELJASVAARA ◽  
Ildiko VERESS ◽  
Maria HALMEKYTÖ ◽  
Leena ALHONEN ◽  
Juhani JÄNNE ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Ornithine Decarboxylase ◽  
Metabolic Flux ◽  
Pulse Labelling ◽  
Spermidine Synthase ◽  
Tissue Concentrations ◽  
Adenosylmethionine Decarboxylase ◽  
Normal Limits ◽  
Primary Fibroblasts ◽  
Hybrid Mice

Recent work has shown that transgenic mice overexpressing human ornithine decarboxylase display no marked changes in the tissue concentrations of spermidine or spermine in spite of a dramatic increase in putrescine levels. In the tissues of transgenic mice carrying the human spermidine synthase gene and in those of hybrid mice overexpressing both ornithine decarboxylase and spermidine synthase, spermidine and spermine levels remain within normal limits. To test whether the amount of the propylamine group donor, decarboxylated S-adenosylmethionine, limits the conversion of putrescine into the higher polyamines, we have produced transgenic mouse lines harbouring the rat S-adenosylmethionine decarboxylase gene in their genome. However, neither these mice nor the hybrid mice overexpressing both ornithine decarboxylase and S-adenosylmethionine decarboxylase displayed significant changes in their spermidine and spermine tissue levels. To study the mechanism by which cells maintain the constancy of the polyamine concentrations, we have determined the metabolic flux of polyamines in transgenic primary fibroblasts using pulse labelling. The results indicate that the polyamine flow is faster in transgenic primary fibroblasts than in non-transgenic fibroblasts and that the intracellular homoeostasis of higher polyamines is maintained at least partly by the acetylation of spermidine and spermine and their secretion into the medium.

scholarly journals Response of enzymes involved in the metabolism of polyamines to phytohaemagglutinin-induced activation of human lymphocytes

1981 ◽  
Vol 196 (3) ◽  
pp. 733-738 ◽  
Author(s):  
H Korpela ◽  
E Hölttä ◽  
T Hovi ◽  
J Jänne
Keyword(s):  
Ornithine Decarboxylase ◽  
Human Lymphocytes ◽  
Lymphocyte Activation ◽  
Decarboxylase Activity ◽  
Spermidine Synthase ◽  
Irreversible Inhibitor ◽  
Adenosylmethionine Decarboxylase ◽  
Spermine Synthase ◽  
Diamine Oxidase Activity ◽  
Stimulation Of

The stimulation of lymphocyte ornithine decarboxylase and adenosylmethionine decarboxylase produced by phytohaemagglutinin was accompanied by an equally marked, but delayed, stimulation of spermidine synthase, which is not commonly considered as an inducible enzyme. In contrast with the marked stimulation of these biosynthetic enzymes, less marked changes were observed in the biodegradative enzymes of polyamines in response to phytohaemagglutinin. Diamine oxidase activity was undetectable during all stages of the transformation. The activity of polyamine oxidase remained either constant or was slightly decreased several days after addition of the mitogen. The activity of polyamine acetylase (employing all the natural polyamines as substrates) distinctly increased both in the cytosolic and crude nuclear preparations of the cells during later stages of mitogen activation. Difluoromethylornithine, an irreversible inhibitor of ornithine decarboxylase, although powerfully inhibiting ornithine decarboxylase, produced a gradual enhancement of adenosylmethionine decarboxylase activity during lymphocyte activation, without influencing the activities of the two propylamine transferases (spermidine synthase and spermine synthase).

scholarly journals Characterization of transgenic mice with widespread overexpression of spermine synthase

2004 ◽  
Vol 381 (3) ◽  
pp. 701-707 ◽  
Author(s):  
Yoshihiko IKEGUCHI ◽  
Xiaojing WANG ◽  
Diane E. McCLOSKEY ◽  
Catherine S. COLEMAN ◽  
Paul NELSON ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Ornithine Decarboxylase ◽  
Strong Support ◽  
Normal Growth ◽  
Early Gene ◽  
Transgenic Expression ◽  
Adenosylmethionine Decarboxylase ◽  
Spermine Synthase ◽  
Gene Enhancer ◽  
Actin Promoter

A widespread increase in SpmS (spermine synthase) activity has been produced in transgenic mice using a construct in which the human SpmS cDNA was placed under the control of a composite CMV-IE (cytomegalovirus immediate early gene) enhancer–chicken β-actin promoter. Four separate founder CAG/SpmS mice were studied. Transgenic expression of SpmS was found in all of the tissues examined, but the relative SpmS activities varied widely according to the founder animal and the tissue studied. Very large increases in SpmS activity were seen in many tissues. SpdS (spermidine synthase) activity was not affected. Although there was a statistically significant decline in spermidine content and increase in spermine, the alterations were small compared with the increase in SpmS activity. These results provide strong support for the concept that the levels of the higher polyamines spermidine and spermine are not determined only by the relative activities of the two aminopropyltransferases. Other factors such as availability of the aminopropyl donor substrate decarboxylated S-adenosylmethionine and possibly degradation or excretion must also influence the spermidine/spermine ratio. No deleterious effects of SpmS overexpression were seen. The mice had normal growth, fertility and behaviour up to the age of 12 months. However, breeding the CAG/SpmS mice with MHC (α-myosin heavy chain)/AdoMetDC (S-adenosylmethionine decarboxylase) mice, which have a large increase in S-adenosylmethionine decarboxylase expression in heart, was lethal. In contrast, breeding the CAG/SpmS mice with MHC/ODC (L-ornithine decarboxylase) mice, which have a large increase in cardiac ornithine decarboxylase expression, had a protective effect in preventing the small decrease in viability of the MHC/ODC mice.

scholarly journals Role of propylamine transferases in hormone-induced stimulation of polyamine biosynthesis

1980 ◽  
Vol 192 (1) ◽  
pp. 59-63 ◽  
Author(s):  
Kirsti Käpyaho ◽  
Hannu Pösö ◽  
Juhani Jänne
Keyword(s):  
Seminal Vesicle ◽  
Ornithine Decarboxylase ◽  
Ovarian Tissue ◽  
Ventral Prostate ◽  
Decarboxylase Activity ◽  
Spermidine Synthase ◽  
Polyamine Biosynthesis ◽  
Adenosylmethionine Decarboxylase ◽  
Spermine Synthase ◽  
Stimulation Of

The effect of various hormones on the activities of the four enzymes engaged with the biosynthesis of the polyamines has been investigated in the rat. Human choriogonadotropin induced a dramatic, yet transient, stimulation of l-ornithine decarboxylase (EC 4.1.1.17) activity in rat ovary, with no or only marginal changes in the activities of S-adenosyl-l-methionine decarboxylase (EC 4.1.1.50), spermidine synthase (aminopropyltransferase; EC 2.5.1.16) or spermine synthase. A single injection of oestradiol into immature rats maximally induced uterine ornithine decarboxylase at 4h after the injection. This early stimulation of ornithine decarboxylase activity was accompanied by a distinct enhancement of adenosylmethionine decarboxylase activity and a decrease in the activities of spermidine synthase and spermine synthase. In the seminal vesicle of castrated rats, testosterone treatment elicited a striking and persistent stimulation of ornithine decarboxylase and adenosylmethionine decarboxylase activities. The activity of spermidine synthase likewise rapidly increased between the first and the second day after the commencement of the hormone treatment, whereas the activity of spermine synthase remained virtually unchanged during the whole period of observation. Testosterone-induced changes in polyamine formation in the ventral prostate were comparable with those found in the seminal vesicle, with the possible exception of a more pronounced stimulation of spermidine synthase activity. It thus appears that an enhancement in one or both of the propylamine transferase (aminopropyltransferase) activities in response to hormone administration is an indicator of hormone-dependent growth (uterus and the male accessory sexual glands), and is not necessarily associated with non-proliferative hormonal responses, such as gonadotropin-induced luteinization of the ovarian tissue.

scholarly journals Transgenic mice over-producing putrescine in their tissues do not convert the diamine into higher polyamines

1993 ◽  
Vol 291 (2) ◽  
pp. 505-508 ◽  
Author(s):  
M Halmekytö ◽  
L Alhonen ◽  
L Alakuijala ◽  
J Jänne
Keyword(s):  
Transgenic Mice ◽  
Transgenic Mouse ◽  
Ornithine Decarboxylase ◽  
Specific Inhibitor ◽  
Mouse Line ◽  
Transgenic Mouse Line ◽  
Adenosylmethionine Decarboxylase ◽  
Adult Tissues ◽  
Ornithine Transaminase

We recently described a transgenic mouse line over-expressing the human ornithine decarboxylase gene virtually in all tissues. Despite strikingly elevated tissue putrescine concentrations, no or minimal changes were found in the levels of the higher polyamines spermidine and spermine. We have now extended these studies by further increasing tissue putrescine with the aid of 5-fluoromethylornithine, a specific inhibitor of ornithine transaminase and hence the catabolism of L-ornithine. As a result of the treatment with the latter drug, the concentration of putrescine was further increased by a factor of 2-3 without any changes in the concentrations of spermidine and spermine. In the testis of transgenic mice treated with 5-fluoromethylornithine, the concentration of putrescine was nearly 60 times that in non-transgenic untreated animals, yet the concentration of spermidine was only 1.5-fold higher. A similar small increase in brain spermidine was accompanied by a 40-fold elevation in the concentration of putrescine. The apparent blockade between putrescine and spermidine was in all likelihood not attributable to an inhibition of S-adenosylmethionine decarboxylase, the rate-controlling enzyme in the biosynthesis of spermidine and spermine. Our results are more compatible with the view that in non-dividing adult tissues putrescine is sequestered through some unknown mechanisms in a way that makes it unavailable for the synthesis of the higher polyamines.

scholarly journals Overproduction of cardiac S-adenosylmethionine decarboxylase in transgenic mice

2005 ◽  
Vol 393 (1) ◽  
pp. 295-302 ◽  
Author(s):  
Oleg Nisenberg ◽  
Anthony E. Pegg ◽  
Patricia A. Welsh ◽  
Kerry Keefer ◽  
Lisa M. Shantz
Keyword(s):  
Transgenic Mice ◽  
Ornithine Decarboxylase ◽  
Fold Increase ◽  
Adrenergic Stimulation ◽  
Compensatory Mechanisms ◽  
Specific Expression ◽  
Adenosylmethionine Decarboxylase ◽  
Cardiac Phenotype ◽  
Founder Line ◽  
Do So

The present study was designed to provide a better understanding of the role played by AdoMetDC (S-adenosylmethionine decarboxylase), the key rate-controlling enzyme in the synthesis of spermidine and spermine, in controlling polyamine levels and the importance of polyamines in cardiac physiology. The αMHC (α-myosin heavy chain) promoter was used to generate transgenic mice with cardiac-specific expression of AdoMetDC. A founder line (αMHC/AdoMetDC) was established with a >100-fold increase in AdoMetDC activity in the heart. Transgene expression was maximal by 1 week of age and remained constant into adulthood. However, the changes in polyamine levels were most pronounced during the first week of age, with a 2-fold decrease in putrescine and spermidine and a 2-fold increase in spermine. At later times, spermine returned to near control levels, whereas putrescine and spermidine levels remained lower, suggesting that compensatory mechanisms exist to limit spermine accumulation. The αMHC/AdoMetDC mice did not display an overt cardiac phenotype, but there was an increased cardiac hypertrophy after β-adrenergic stimulation with isoprenaline (‘isoproterenol’), as well as a small increase in spermine content. Crosses of the αMHC/AdoMetDC with αMHC/ornithine decarboxylase mice that have a >1000-fold increase in cardiac ornithine decarboxylase were lethal in utero, presumably due to increase in spermine to toxic levels. These findings suggest that cardiac spermine levels are highly regulated to avoid polyamine-induced toxicity and that homoeostatic mechanisms can maintain non-toxic levels even when one enzyme of the biosynthetic pathway is greatly elevated but are unable to do so when two biosynthetic enzymes are increased.

scholarly journals Transgenic mice over-expressing the human spermidine synthase gene

1993 ◽  
Vol 293 (2) ◽  
pp. 513-516 ◽  
Author(s):  
L Kauppinen ◽  
S Myöhänen ◽  
M Halmekytö ◽  
L Alhonen ◽  
J Jänne
Keyword(s):  
Transgenic Mice ◽  
Reverse Transcriptase ◽  
Human Gene ◽  
Transgenic Animals ◽  
Chromosome 1 ◽  
Pcr Analysis ◽  
Spermidine Synthase ◽  
Mouse Line ◽  
Transgenic Mouse Line ◽  
Adenosylmethionine Decarboxylase

We have generated a transgenic mouse line harbouring the functional (chromosome-1-derived) human spermidine synthase (EC 2.5.1.16) gene in their genome. The transgenic animals expressed the human gene-derived mRNA, as revealed by reverse-transcriptase/PCR analysis, in all tissues studied and displayed tissue spermidine synthase activity that was 2-6 times that in their syngenic littermates. The elevated spermidine synthase activity, however, had virtually no effect on tissue putrescine, spermidine or spermine levels. The view that the accumulation of spermidine and spermine is possibly controlled by S-adenosylmethionine decarboxylase was further supported by the finding that tissue spermidine and spermine contents also remained practically normal in hybrid transgenic mice over-expressing both human ornithine decarboxylase and spermidine synthase genes.

Polyamine biosynthetic enzymes as drug targets in parasitic protozoa

2003 ◽  
Vol 31 (2) ◽  
pp. 415-419 ◽  
Author(s):  
O. Heby ◽  
S.C. Roberts ◽  
B. Ullman
Keyword(s):  
Chagas Disease ◽  
Ornithine Decarboxylase ◽  
Infected Patient ◽  
Drug Targets ◽  
Genetic Characterization ◽  
Biosynthetic Enzymes ◽  
Spermidine Synthase ◽  
Growth And Survival ◽  
Adenosylmethionine Decarboxylase

Molecular, biochemical and genetic characterization of ornithine decarboxylase, S-adenosylmethionine decarboxylase and spermidine synthase establishes that these polyamine-biosynthetic enzymes are essential for growth and survival of the agents that cause African sleeping sickness, Chagas' disease, leishmaniasis and malaria. These enzymes exhibit features that differ significantly between the parasites and the human host. Therefore it is conceivable that exploitation of such differences can lead to the design of new inhibitors that will selectively kill the parasites while exerting minimal, or at least tolerable, effects on the parasite-infected patient.

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